There is a growing interest in exhaled nitric oxide (NO) as a non-invasive marker of pulmonary inflammation and oxidative stress. Previous studies has focused on use of exhaled NO to diagnose and monitor the airway inflammation in spontaneously breathing patients. However, few studies have involved mechanically ventilated (MV) patients. Airway inflammation and oxidative stress during MV tend to predispose to more serious complications, such as acute lung injury. Thus exhaled NO analysis may also have a potential use in MV patients. As an initial step, it is necessary to explore changes in levels of exhaled NO and its serum marker (serum nitrite [sNO2- ]) over time in patients who require an artificial airway (which disrupts normal NO flow from the nose to the lower airways) and MV (which introduces confounding factors). The purpose of this study is to examine changes in exhaled NO from the nose (nNO), exhaled NO from the lower airways (LNO) and sNO2- over time in: 1) spontaneously breathing patients undergoing tracheostomy or laryngectomy (T/L), and 2) patients undergoing tracheostomy while on MV (T-MV). A prospective, 2x3 repeated measures design will be used. Comparisons will be made between nNO, LNO and sNO2- obtained 1) pre-T/L, Day 1-3 post-T/L, and 1 week after in T/L patients, and 2) pre-tracheostomy, Day 1-3 post-tracheostomy, and 1 week after in T-MV patients. Statistical analysis will include descriptive statistics, 2x3 repeated measures MANCOVA, 1 way repeated measures ANOVA and Sperman's rank correlation.